1. Air Emissions from Composting 10 YEARS OF RESEARCH AND REGULATORY ACTION IN CALIFORNIA Robert Horowitz California Dept. of Resources, Recycling & Recovery (CalRecycle) robert.horowitz@CalRecycle.ca.gov

2. This Presentation 1.California law and composting 2.Do compost emissions lead to harmful air pollution? 3.Air Pollution Control Districts 4.Composting emissions research 5.Climate change research 2

3. California Law  Cities and counties must divert >50% of their solid waste away from landfills or CalRecycle can issue fines  Composting IS recycling  NEW: CA recycling goal: 75% by 2020  NEW: Businesses with >4 cubic meters of garbage per week must recycle  NEW: Apartment buildings with 5 or more units must offer recycling to residents 3

4. Composting in California  Most facilities compost source separated green waste in open windrows  115 facilities / @4 million tons processed  Most compost sold to agriculture, but farmers do not want to pay too much  New air- and water-quality regulations will require major facility upgrades  Economics do not support engineered facilities

5. 5 Open-windrow composting 20 hectare green waste facility near Modesto, CA

6. Do composting emissions lead to harmful air pollution?  Compost piles emit Volatile Organic Compounds (VOCs)  When reactive VOCs mix with oxides of nitrogen (NOx), in the presence of sunlight, photochemical “smog” results  Smog includes ground-level ozone  Ozone is very harmful to human health, as well as plants and agricultural crops  US Clean Air Act regulates ozone levels, mandates action to cut precursors like VOCs 6

7. 7 Ozone non-attainment areas in the USA Source: USEPA 8-hour ozone (1997 standard) As of April, 2011

8. 8 California Air Pollution Control Districts Districts enforce federal and state laws, including the Clean Air Act The association of top air district officials is called CAPCOA

9. APCDs and Composting  Two largest districts adopted rules in 2011  At least one other has a compost rule on its calendar for 2012 (Ventura)  CAPCOA survey asking all districts if they don’t regulate composting-why not?  San Joaquin now enforcing New Source Review for new/expanded compost sites  New interpretation of rules regarding portable equipment 9

10. Common features of APCD rules  Enhanced record keeping: materials in & out and materials into windrows  Feedstock holding time limits  Wet top of windrow before turning  Pseudo-biofilter compost cap on active windrows. Replace the cap if you turn  Aerated systems with emissions capture for the largest facilities  Annual inspections 10

11. New Source Review in the SJV  Best Available Control Technology (BACT) required for :  Any new facility with VOC emissions greater than 10 tons per year  Any expanded facility with VOC increase greater than 2 pounds per day  SJV emissions factor 5.71 lbs of VOC per ton of greenwaste feedstock = 3500 tpy composting  You must purchase offsets for each ton of emissions over 10 tons per year 11

12. Yolo – Solano AQMD  Facilities grandfathered in at existing emissions set in baseline study  You can increase throughput but you cannot increase emissions  Source testing of new system to ensure emissions are reduced overall 12

13. Portable equipment permitting  Equipment essential to operation of composting facility is NOT portable  ARB tightened emissions standards for portable diesel equipment  Hundreds of grinders and trommels registered with ARB as portable, some incorrectly  CAPCOA seeking consistent application of stringent portability standard  APCDs can and will issue violations 13

14. 1996-2002 Emissions Studies Southern California—AQMD & CalRecycle  First attempts in CA to quantify emissions factors for composting facilities  CalRecycle helped with concurrent testing using lasers, and studied process controls  Established emissions factors in pounds of pollutant per ton of feedstock  Emissions factors allow APCDs to estimate emissions from a facility based on throughput 14

15. 15 2005-6 CalRecycle Study Modesto - Northern California  70-80% of total VOCs emitted during 1 st two weeks  70-85% of total VOC emissions vent through top of windrow  “Pseudo-biofilter” compost cap reduced VOC emissions up to 75% for first two weeks.  Additives reduced VOC emissions 42% for first week; 14% for first two weeks  15% food waste roughly doubled VOC emissions compared to “straight” green waste  Lifecycle VOC emissions from pure greenwaste windrow 1 lb per ton of feedstock

16. Pseudo-biofilter compost cap  15 cm layer of unscreened finished compost or overs on top of actively composting pile  Takes advantage of natural pile convection Cap layer Active compost pile Airflow Warm pile core

17. 2009 San Joaquin APCD study 17 Study: Irrigation system used for 3 hours before turning reduced emissions by 24% over first 3 weeks New Rule 4566: Facilities between 10,000- 200,000 tons/year must achieve 24% reduction Study: Pseudo-biofilter compost cap reduced emissions by 53% over first three weeks. New Rule 4566: Facilities over 200,000 tpy must achieve 53% emissions reduction

18. 2009-2011 Compost Emissions Reactivity Studies  Not all VOCs are equal; focus on ozone formation potential (OFP)  Compare modeled ozone formation to ozone measured in portable chamber  Tested OFP of windrows, tip piles, overs  Tested impact on OFP of a pseudo-biofilter cap made of composting overs  Proven method used at many agricultural sites in San Joaquin Valley 18

19. Mobile Ozone Chamber 19  Holds 1000-liter teflon bag  3-hour experiments  Used at many ag sites

20. What kinds of emissions?  80-95% light alcohols: ethanol, methanol, isopropyl alcohol  More than 80 other compounds  1-3% highly reactive terpenes, aldehydes 20 TOP COMPOUNDS IN COMPOSTING EMISSIONS Isopropyl alcohol Ethanol Methanol Acetic Acid Limonene Camphor Alpha Pinene 3 hydroxy 2 butanone Butanoic acid Eucalyptol Methylthymyl ether Bornyl acetate Pinene isomer

21. More 2010-2011 results  Reactivity of greenwaste and biosolids composting emissions: LOW  Overs cap effective in reducing observed ozone formation by 27-36%  Composting similar to other agricultural sources, such as manure  Typical urban air @3x more reactive than composting emissions 21

22. Maximum Incremental Reactivity scale (MIR)* 22

23. Composting GHG study  Funded by CalRecycle  Research conducted by Univ. Calif.  Focus on N 2 0 and CH 4  Field work 2010-2013  Final report May, 2014  Concurrent with and complementary to other ongoing ag GHG studies 23

24. Dual approach 24 1. Measure CH 4 and N 2 0 from composting windrows of green waste and food waste 2. Measure N 2 0 and CH 4 emissions from compost amended and conventionally fertilized croplands

25. 25 Increasing compost use… …may decrease use of less sustainable methods.

26. Related Web Pages  My CalRecycle web page: http://www.calrecycle.ca.gov/Organics/Air/default.htm http://www.calrecycle.ca.gov/Organics/Air/default.htm  CalRecycle Greenwaste Compost Reactivity Study: http://www.calrecycle.ca.gov/Publications/Organics/2011006.pdf http://www.calrecycle.ca.gov/Publications/Organics/2011006.pdf  CASA Biosolids Co-compost Reactivity Study http://casaweb.org/documents/2011/werf2c10_web.pdf http://casaweb.org/documents/2011/werf2c10_web.pdf  CalRecycle/Modesto Compost Study http://www.calrecycle.ca.gov/publications/Organics/44207009.pdf http://www.calrecycle.ca.gov/publications/Organics/44207009.pdf  Composting: Feedstock control vs. Aeration study http://www.calrecycle.ca.gov/Publications/Organics/2008016.pdf http://www.calrecycle.ca.gov/Publications/Organics/2008016.pdf  Comprehensive Composting Odor Response Project http://www.calrecycle.ca.gov/Publications/Organics/44207001.pdf http://www.calrecycle.ca.gov/Publications/Organics/44207001.pdf 26

27. Summary Air pollution regulators are increasingly aware of composting sites as emissions sources Both pile emissions and equipment will face increasingly stringent limits Composting VOCs around 1/3 as potent as average urban air for ozone formation Pseudo-biofilter compost cap effective in reducing emissions and odors Greenhouse gas impacts of compost production and use need further research 27

28. Thank You Bob Horowitz (916) 341-6523 Robert.Horowitz@CalRecycle.ca.gov http://www.calrecycle.ca.gov/Organics/Air/default.htm